méthode de la pression critique de bordure

CONT: Critical lip pressure method ... If hot water or a water/steam mixture is discharged at sonic velocity through an open-ended pipe, and if the pressure is measured at the discharge lip of the pipe, this pressure is a measure of the heat flow of the discharged fluid. James has deduced ... [a] formula expressed in f.p.s. units ... Where the two phases of a water/steam mixture are segregated by means of a cyclone separator the water can be measured either by a cooled orifice or, after allowing for the flashed steam, by means of a V-notch or weir. Alternatively, however, the water may simply be discharged at sonic velocity through an open-ended pipe and measured by applying ... [James] formula. By measuring the temperature of the water leaving the separator its enthalpy is made known, and ... [the flow] can be deduced from ... [the critical lip pressure].